Field of the Invention
The invention relates to a semiconductor light source with an epitaxially grown layer stack for generating photons and emitting photons and to a method for the production thereof.
Transparent infrared diodes (IREDs) and light emitting diodes (LEDs) are examples of light sources of this type. The layers of the layer stack of such light sources are grown epitaxially in succession on a growth substrate in the form of a crystal. Part of the photons generated in the layer stack are emitted from the stack in the direction of the growth substrate and are absorbed there.
For such semiconductor light sources of optimally high optical performance the attempt is made largely to avoid the absorption in the growth substrate. Besides the utilization of growth substrates that are transparent for the photons, which is possible in a few cases, Bragg reflectors formed of semiconductor material inserted between the growth substrate and the grown layer stack, or the postattachment of a supporting body to the layer stack where that body is transparent for the photons--e.g. by means of wafer bonds--are the means used for this.
In the postattachment of the transparent supporting body at the layer stack, the supporting body is connected in a planar and intimate fashion to the surface of the layer stack that is turned away from the growth substrate such that the supporting body is connected directly to the layer stack just as securely as the growth substrate itself. This direct attachment is carried out by casting the transparent supporting body to the layer stack. Subsequent to the attachment, the growth substrate is removed from the layer stack, whereupon the layer stack and the transparent supporting body are present together as a unified composite body similar to the previous layer stack and growth substrate and the transparent supporting body supports the layer stack now as the growth substrate did originally. In this condition the layer stack is electrically contacted or bonded.